I have more than 100 drawings I want to import to QCAD 3.0.The drawings are made on a 3-D CAD program with name Pro Desktop Express 8 /Built on Granite (PTC).

As I understand the drawings are in 2-D format, and can be exported as file typeDWG, DXF or binary DXF. The file version can be ACAD R10, R11, R13, R14 or ACAD 2000.

I have had some success in importing DXF file type to QCAD. I could open the drawingbut if I edited a text string and saved the file and opened it again I got a blank window.The drawing file had still the same size on disk but was not seen. I got a message sayingthe lines colour were changed to white and therefore not seen.Can I change the colour for that layer to black and make it seenable again?

Anyone that can give me a hint of combination of file type and version to usewhen exporting from PTC CAD program?

All DXF/DWG format versions <= 2000 don't have a color value for black which is why QCAD has to change all black colored entities and layers to white when exporting to those format versions.

To keep all colors unchanged, save the file as DXF or DWG version >2000 (File - Save As - Format: R2004, R2007 or R2010).

Note that QCAD by default adjusts the display color of entities to never match the background if the background is black or white. You might have disabled this setting under Edit - Application Preferences - Graphics View - Color Adjustment